Project summary/abstract: This training grant seeks funding to support the career development of Dr. Ryan Solinsky, a Physical Medicine & Rehabilitation physician-scientist at Spaulding Rehabilitation Hospital and Harvard Medical School, Boston, Massachusetts. Dr. Solinsky is establishing himself as an early career investigator in the clinical application and translation of autonomic neuroscience to improve functional outcomes for individuals after spinal cord injury. This K23 award will provide Dr. Solinsky the necessary support to accomplish the following training goals: 1) Broaden his understanding in computational neuroscience, with a focus on developing expertise in direct sympathetic nervous system recordings and spike train decoding, and in ambulatory monitoring of autonomic indicators; 2) Develop novel functional autonomic neuroimaging through collaboration with local experts 3) Grow his expertise in advanced statistical methods, appropriate for small-n studies of often heterogeneous populations such as those with spinal cord injury; and 4) Expand research project management, grantsmanship, and clinical research skills. To achieve these goals, Dr. Solinsky has developed a training plan with Dr. J. Andrew Taylor as his primary mentor. Dr. Taylor is a well-respected PhD scientist, with research expertise in autonomic control of the cardiovascular system as well as how this system is affected by exercise, specifically in individuals with spinal cord injury. Dr. Solinsky will have additional co-mentors: Dr. Teresa Kimberley, PT, PhD whose research focuses on translation of autonomic neuromodulation to improve outcomes after neurologic disease, and Dr. Roy Freeman, MBChB, a Neurologist and researcher specializing in clinical assessments of autonomic dysfunction. Further collaborators with expertise in functional neuroimaging, advanced statistical methods, and clinical spinal cord injury care are included in this proposal, which will be headquartered at Spaulding Rehabilitation Hospital in Boston, Massachusetts. Autonomic dysfunction following spinal cord injury is a significant clinical issue contributing to mortality and increased healthcare costs. Unfortunately, our understanding of autonomic dysfunction in this population is in its infancy. The overall objective of this research proposal is to characterize cardiovascular autonomic dysfunction after spinal cord injury using a battery of laboratory, ambulatory, and imaging-based tools. These will be focused on cardiovascular autonomic function, as this has the highest potential for clinical translation, with correlative structures to other components of the autonomic nervous system investigated. Research will specifically look to answer two questions: 1) Can discrete cardiovascular autonomic phenotypes be identified within those with spinal cord injury and correlated to clinical secondary autonomic complications? 2) Do those with the most dysregulated cardiovascular autonomic phenotypes demonstrate the highest rates of aberrant spinal cord functional connectivity on fMRI? Answering these questions will help us understand how autonomic regulation changes after spinal cord injury and how alterations translate to clinical secondary complications.